RAID (Redundant Array of Idle/Independent Disks) has evolved significantly since the original RAID white paper from the University of California Berkeley (Patterson, Gibson & Katz) was published 20 some years ago and in many cases is taken for granted today. There is also debate as to whether RAID is still relevant and practical given the continued increase amounts of data that needs to be protected.

Sample of some common RAID levels, general characteristics, caveat and benefits